Rod-packing



(No Model.)

G. W. 'KN'oWLToN Ron PACKING..

No. 487,019 Patented Nov. 29, 1892.

55-1, Falz- WITNEESEE- UNITEDSTTES PATENT y,()F1r1`cf11a A(menen W. KNOWLTON,V on BOSTON, MASSACHUSETTS;

Ron-PACKING;

SPECIFICATION forming pm of Letters Patent No. 487,019, antea- November 29, 1892.

Application iiled June 13, 1892. Serial No. 436,426. '(No model.) i

.To' all whom-it may concern,.-

Be it known that I, GEORGE W. KNOWLTON,

of Boston, in thevcounty of Suffolk and'State of Massachusetts,-have invented certain new and'usef u1 Improvements in Piston-Rod Packing's 'and-the Method of MakiiigtheSame, of

-which the following is a specification'. A l 'I his inventionlhas for its object to provide a permanently formed or molded piston-rod packing of ring form, composed in. part of rubber and adapted to preserve a'tight joint and compensatefor wear ofthe rod, as well as for depressions caused by defects in aworn -rod.

The invention 'consists ina packing composed of a ring permanently formed or molded to fit a piston-'rod and comprising in its construction, first, an'inner section composed of a .strip or strips of duck or other suitable brousmaterial cut bias and arranged in the .form'of a helix, itsconvolutions being placed with. their fiat sides in contact with each other, cemented together and molded, so as to form a-tube adapted ,to encircle the pistonjrod, the inner edges of the convolutions collectively forming the internal surface of the tube, which bears upon the rod andpresenting a crossed-edge surface composed of the' ends of the threads Vof the fabric, as 'the wearing-surface; second, 'a section composedv of partially-vulcanized,'compressedmnd molded rubber arranged asa ring, covering the outer' surface of the tiretnamed or inner section, and, third, an outer section of. any suitable .material and construction adapted to protect the rubber section, said outer and inner sec-v tions being preferably saturated with a suitable lubricant to render them pliable.

The invention also consists-in certain improvements in the method of. making ringpacking, all asihereinafter. described;

`In the accompanying drawings, forming aapart ofthe ibrous strip from .which the in- A In carrying-lont my lnv'ention I make, ai

ner section of the packing is made. The same letters of reference indicate same parts in all 'of the Iigures.

the.' elastic and will at the sametimeresist-'the heat tovvhich the packing is subjected wher 4packing composed of an inner section a), an

outer section'b, and an 'intermediate section c, the-inner section'beingfformed to tit closely on the piston-rod. The inner section-is composed of a strip of duck or other suitable textile fabric eut bias, as shown in Fig. 4, and wound helically around a suitable cylindrical former,` the convolutions ofthestrip being arranged with their flatsides in contact with` each other and substantially at right angles to thejlength ofthe piston-rod surrounded'by the packing; .The inner edges of the convollutions comprising one edge of the strip from whichthe convolutions are madeconstitute the wearing-surface. of the packing and bearl upon the piston-rod, The convol'utions of the" strip a are firmly united by-means of rubber or other suitable cement interposedv between vof t-heconvolutions dnringthe operation of forming the same,so tl1at-theiinnersectionisa; permanently formedorlmolded ring adapted f Lto lita piston-rod, the cement being applied in a manner well known to those skilled in. the art of vtreating rubber.v The intermediate section c is a continuous molded 'ring of par- Y tially-vulcanized rubber. formed uponthe outer surface of the inner section a.- By the term ,partally-vulcanized rubber I mean rubber originally treated so that it will only be partially1 vulcanized by the degree ot'4 heat to which a p iston-rodpackingis subjectedin its ordinary'use. placed in an entirely-unvulcanized condition onthe innei section ct and formsa continuous The rubber thus treated is ring of soft .rubber surrounding said inner section 'and adheringclosely thereto. The` outer section b maybe composed of a'strip of duck or other suitable textile material wound upon the exterior of the rubber section c, the object of the outer section bei ng to prevent box and to prctect the rubber'. Hence it may' beof anysuitable construction and material.

.contact between the rubber' and the stuitingand pressure in a vulcanizing melder flask'y until the rubber section isl partially vulcanized, or,-'-n` yother words`,'is So changed from loe its condition prior tothe application of heatf The ring made lip-of: the three section`s,as above described, is then subjected to heat 2 t esame vin usewithout being either melted or vulcanized to hardness thereby.v rihe pressure to which the packing is subjected while the rub-l ber isbeing partially vulcanized firmly unites the rubber section to the outer and inner sec,- tions and compresses the rubber, so that it ispartially vulcanized in a compressed condition and immediately expands when put to use on a piston-rod. Hence the packing can be tightened or forced -intcw place by a light pressure, such as can be exerted by the iingers,and gives the highest results that can be obtained in a packing-viz., a tight joint with the least possible friction. The ring thus formed'is preferably severed or cut through diagonally at one side, 'so that it can lbe enlarged or contracted.

I claim- 1 l. The improved rod-packing hereinbefore described, composed of a ring molded and formed to it a piston-rod and havingrelavtively-inelastic inner and outer sections and an intermediate elastic section of partiallyvulcanized lrubber, said rubber being in a layers or convolutions, forming a tube, the l Isides of the layers or convolutions being partially-compressed state, as set forth.'

2. The improved ring packinghereinbefore described, the'same consisting of three parts,

namely: 4girst, the permanently formed or molded inner section made of a strip or strips of textile fabric cut bias and arranged in c ementetltogether and arranged substant1ally at right angles with the length of the rod encircled by the packing', while their inner edges collectively constitute the wearing surface of the packing and present the ends of the threads at said surface; secondly, the intermediate4 section or continuous molded ring` of partially-vulcanized rubber inclosing the inner section, said rubber being in a partially-compressed state, and, thirdly, an outer section adapted lto protect the rubber, the eonvolutions of boththe inner and outer sections being saturated with a lubricant, as set forth.

3. The improved method hereinbefore described of making ring packing, the same consisting in interposing between relativelyinelastic ring-shaped inner andy outer sections a continuous ring-shaped sectionV of unvulcauized rubber prepared to be only par' encuen W. KNoWLroN.

` Witnesses: v

C. F. BROWN, 'J'. MARTIN ALLEN. 

